1 / 25

Fractions: Addition & Subtraction

Next. Fractions: Addition & Subtraction. Lesson 1f. Numerator. Denominator. Fractions Reminder. Fractions have two parts: A Numerator & A Denominator . Next. Finding Common Denominators.

yon
Download Presentation

Fractions: Addition & Subtraction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Next Fractions: Addition & Subtraction Lesson 1f

  2. Numerator Denominator Fractions Reminder • Fractions have two parts: • A Numerator & • A Denominator Next

  3. Finding Common Denominators • Before you can learn to add or subtract fractions you must first learn how to find the LeastCommon Denominator (LCD). • A Common Denominator is a common multiple of all of the denominators Next

  4. A common denominator of and is a common multiple of 3 and 4. • 12 is a common denominator of and . Next Finding Common Denominators Cont. . . Example 1: • Write and as fractions with a common denominator. • List the multiples of 4 until you have a common multiple of 3 and 4. No Is 4 a multiple of 3? 4 8 12 16 No Is 8 a multiple of 3? Is 12 a multiple of 3? Yes • 12 is the Least Common Denominator (LCD).

  5. Next Finding Common Denominators Cont. . . Example 1: cont . . . • Now it is time to find the fractions equal to and that have a denominator of 12. 3 = 3 1 x ? 4 = 8 2 x ? ? ? ? ? 8 ? ? ? ? ? ? 3 = = 4 4 4 4 3 3 3 3 3 x ? = 12 4 x ? = 12 = =

  6. 24 is a common denominator of , & . Next Finding Common Denominators Cont. . . Example 2: • Write , and as fractions with a common denominator. • List the multiples of 8 until you have a common multiple of 2, 3 and 8. No Is 8 a multiple of 2 & 3? 8 16 24 Is 16 a multiple of 2 & 3? No Is 24 a multiple of 2 & 3? Yes • 24 is the Least Common Denominator (LCD).

  7. Next Finding Common Denominators Cont. . . Example 2: cont . . . • Now it is time to find the fractions equal to , & that have a denominator of 24. 8 = 8 1 x ? 3 = 15 5 x ? 12 =12 1 x ? 12 ? ? ? ? ? ? ? ? ? ? ? ? ? ? 8 15 = = = 8 8 8 8 3 3 3 3 2 x ? =24 3 x ? =24 8 x ? =24 12 12 12 12 = = =

  8. Next Finding Common Denominators Cont. . . Your turn: On a separate sheet of paper, write the following fractions with common denominators. Click here to check your answers!

  9. Next Finding Common Denominators Cont. . . Your turn: On a separate sheet of paper, write the following fractions with common denominators. LCD = 20 LCD = 6 LCD = 10 15 2 8 4 5 5 LCD = 24 LCD = 30 LCD = 30 4 20 9 9 21 25

  10. Reduce to lowest terms Reduce to lowest terms Next Adding & Subtracting Fractions • To add fractions that already have common denominators, add the numerators. • For example: ? 12 • To subtract fractions that already have common denominators, subtract the numerators. • For example: ? 4

  11. Next Adding & Subtracting Fractions Cont. . . Your turn: On a separate sheet of paper, add or subtract the following fractions. Click here to check your answers!

  12. Next Adding & Subtracting Fractions Cont. . . Your turn: On a separate sheet of paper, add or subtract the following fractions. ? 7 16 4 ? ? 6 1 ? 2 ? ?

  13. Next Adding & Subtracting Fractions Cont. . . • To add fractions that do not have common denominators, you must first write each fraction with a common denominator. Then add the numerators. • Example 1: 6 ? ? ? ? • Example 2: 8 9 ? ? ? ? ? ? ? ?

  14. Next Adding & Subtracting Fractions Cont. . . • To subtract fractions that do not have common denominators, you must first write each fraction with a common denominator. Then subtract the numerators. • Example 1: 14 ? ? ? ? • Example 2: 18 15 ? ? ? ? ? ? ? ?

  15. Next Adding & Subtracting Fractions Cont. . . Your turn: On a separate sheet of paper, add or subtract the following fractions. Click here to check your answers!

  16. Next Adding & Subtracting Fractions Cont. . . Your turn: On a separate sheet of paper, add or subtract the following fractions. 2 10 12 15 14 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 7 4 9 2 16 9

  17. Next Adding Mixed Numbers • To add mixed numbers you must first write each fractional part with common denominators. • Example 1: This can be rewritten as: ? ? ? ? ? ? ? ? 9 10

  18. Next Adding Mixed Numbers Cont. . . • To add mixed numbers you must first write each fractional part with common denominators. • Example 2: This can be rewritten as: ? ? ? ? 6

  19. Next Click here to check your answers! Adding Mixed Numbers Cont. . . Your turn: On a separate sheet of paper, add the following fractions.

  20. Next Adding Mixed Numbers Cont. . . Your turn: On a separate sheet of paper, add the following fractions. ? ? ? ? ? ? ? ? ? ? ? ? 15 4 8

  21. 7 10 Next Subtracting Mixed Numbers • To subtract mixed numbers you must first write each fractional part with common denominators. • Example 1: This can be rewritten as: 8 ? ? ? ? 2 – 2 6

  22. must be rewritten. We must borrow 1 from the 6 in order to subtract the fractions. 5 9 Next Subtracting Mixed Numbers Cont. . . • To subtract mixed numbers you must first write each fractional part with common denominators. • Example 1: This can be rewritten as: 5 ? ? ? ? 6 – 4 1

  23. Next Subtracting Mixed Numbers Cont. . . Your turn: On a separate sheet of paper, subtract the following fractions. Click here to check your answers!

  24. 2 4 6 5 Next Subtracting Mixed Numbers Cont. . . Your turn: On a separate sheet of paper, subtract the following fractions. 8 4 – 2 – 3 1 6

  25. The End Time to move on to the next lesson

More Related